Conventionally, it is known that RFL (resorcinol-formaldehyde-latex) adhesive which contains resorcinol, formaldehyde and rubber latex is used for bonding tire cords constituted of polyester fiber or the like and rubber for a tire, and that the adhesive strength is secured by heat curing (see Patent Documents 1 to 3).
It is also known that the adhesive strength is further improved by using a resorcinol-formaldehyde resin which is formed by condensing resorcinol and formaldehyde (see Patent Documents 4 and 5), or pretreating with epoxy resin.